S4 Quattro Wagon V8-4.2L (BHF) (2008)
Checking internal resistance
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Using a Multimeter, check each Knock Sensors' terminals 1 to 2 for an internal short.
Specified value: infinite (Infinity).
If the specified value was not obtained:
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Replace the faulty Knock Sensor (KS) 1 (G61)/or Knock Sensor (KS) 2 (G66) /or Knock Sensor 3 (G198)/or Knock Sensor 4 (G199)Refer to Fuel
Injection and Ignition Repair Information.
If the specified value was obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
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Install the test box. Refer to Fuel Injection and Ignition Repair Information.
If the manufacturers test box is not being used. Perform the following step.
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Remove the Motronic Engine Control Module (ECM) ( J623). Refer to => [ Engine Control Module, Replacing ] See: Computers and Control
Systems/Engine Control Module/Service and Repair
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Using a Multimeter, Check the Knock Sensors' electrical harness connectors to the Motronic Engine Control Module (ECM) (J623) electrical
harness connector T121 for an open circuit.